The present application relates to braze joints in polycrystalline diamond compact cutters.
Drill bits and components thereof are often subjected to extreme conditions (e.g., high temperatures, high pressures, and contact with abrasive surfaces) during subterranean formation drilling or mining operations. A polycrystalline diamond table is often used as an outer portion of polycrystalline diamond compact cutters (“PDC cutters”). The PDC cutters are attached to the drill bit so that the polycrystalline diamond table engages the subterranean formation during drilling. Polycrystalline diamond tables of the PDC cutters have beneficial wear resistance, hardness, and ability to conduct heat away from the point of contact with the formation that enhance the lifetime of the drill bit.
Most commonly, a PDC cutter is formed in a single high-pressure, high-temperature (“HPHT”) press cycle. During the process, diamond particles are placed together with a hard composite substrate in a press. During the press cycle, the diamond particles are sintered, and a catalyzing material facilitates both the bonding between the diamond particles to form a polycrystalline diamond table and to attach the polycrystalline diamond table to the hard composite substrate. In most of the cases, the hard composite provides a source for the catalyzing material (e.g., cobalt, nickel, iron, Group VIII elements, and alloys thereof) that facilitates bonding between the diamond particles. For example, when cobalt-cemented tungsten carbide is the hard composite substrate, the cobalt catalyzing material may melt and enter into the interstitial spaces of the diamond particles. In some instances, catalyzing material may also be mixed with the diamond particles before sintering.